1. Field of the Invention
The invention relates to an image sensor, and in particular to an image sensor having improved radiation effects and arced wires with greater radii of curvature.
2. Description of the Related Art
A general sensor is used to sense signals, which may be optical or audio signals. The sensor of the invention is used to receive image signals or optical signals. After receiving the image signals, the sensor converts the image signals into electrical signals, which are then transmitted to a printed circuit board via a substrate.
Referring to FIG. 1, a conventional image sensor includes a substrate 10, a frame layer 18, a photosensitive chip 26, a plurality of wires 28, and a transparent layer 34. The substrate 10 has a first surface 12 on which a plurality of signal input terminals 15 are formed, and a second surface 14 on which a plurality of signal output terminals 16 are formed. The frame layer 18 has an upper surface 20 and a lower surface 22 adhered to the first surface 12 of the substrate 10 to form a cavity 24 together with the substrate 10. The photosensitive chip 26 is arranged within the cavity 24 and is mounted to the first surface 12 of the substrate 10. Each wire 28 has a first terminal 30 and a second terminal 32. The first terminals 30 are electrically connected to the photosensitive chip 26, and the second terminals 32 are electrically connected to the signal input terminals 15 of the substrate 10. The transparent layer 34 is adhered to the upper surface 20 of the frame layer 18.
However, the above-mentioned image sensor has the following drawbacks.
1. Since the substrate 10 is a ceramic substrate or FR4 printed circuit board on which traces are formed to form the signal input terminals 15 and signal output terminals 16, the overall volume of the substrate 10 is large, the material cost is high, and the package cost is relatively high.
2. Since a gap for wire bonding has to be left between the substrate 10 and the frame layer 18, the package volume is large and the product cannot be miniaturized.
3. Arranging the photosensitive chip 26 on the substrate 10 may have poor radiation effects.
4. Since the wires 28 are bonded to the substrate 10, the radii of curvature of the arced wires may be increased, and the throughput is small.